Automatic fire-alarm.



M. GIBSUN. AUTOMATIC PIRE ALARM..

APPLICATION FILED 00T. 30, 19

'Patented July 9, 1912,

COLUMBIA PLANDGRAPH co..wAsmNGToN'. D, c.

Inventor.

UNITED STATES PATENT oEEioE. i

MALCOLM GIBSON, `OF DAVISVILLE, ONTARIO, CANADA.

AUTOMATIC FIRE-ALARM.

To all whom t may concern.'

Be it known that I, MALCOLM GIBSON, a subject of the King of Great Britain, resident of Davisville, county of York, Province of Ontario, in the Dominion of Canada, have invented certain new and useful Improvements in Automatic Fire-Alarms; and I do hereby declare that the following is a full, clear, and exact description of the same.

The invention relates to improvements in automatic fire alarms, as described in the following specification and illustrated in the accompanying drawing that forms part of the same.

The invention consists essentially in the novel construction and arrangement of parts, whereby an alarm is given on the rising of the temperature to a predeter-` mined point.

The objects of the invention are, to give warning of an undue increase of temperature, thus prematurely stopping fires and to devise an alarm which will ordinarily operate through the rise of a thermometer but will not be rendered inoperative in the event of the thermometer being broken.

Figure 1 of the drawing represents a perspective view of my device Shown partly in section. Fig. 2 is a vertical sectional view showing the thermometer supporting means.

Referring to the drawing, 1 is a plate having the iianges 2 formed at the top and bottom ends, Said plate being adapted to be secured to the wall in a furnace room or any other place where it is desired to locate the alarm.

3 is a bracket adjustably secured to the plate 1 adjacent to the bottom and having a pocket or recess t in the top thereof, said bracket projecting laterally from the front face of said plate.

5 is a thermometer having the bulb end 6 resting in the pocket 1 of the bracket.

7 is a spring tongue secured to the back of the plate 1 and extending through the slot 8 adjacent to the top of said plate, said tongue projecting forwardly and having a pair of pin holes 9 therein.

10 is a bar having a suitable recess formed in its under side midway of its length adapted to receive the top end of the thermometer 5, said bar having the cylindrical portions 11 formed at its outer ends, said cylindrical portions being open at the Specification of Letters Patent.

Application filed October 30, 1911.

Patented July 9, 1912.

serial No. 657,470.

bottom. The spring tongue 7 engages the pins projecting upwardly from the bar 10 thus holding it securelyl in position and holding the thermometer in place.

12 are bolts or binding posts suitably insulated from the plate 1 and extending therethrough, being electrically connected from their inner ends back of said plate to a suitable alarm bell 13, a suitable battery being interposed in the electric circuit.

111 are wires connected to the outwardly projecting ends of the binding posts 12 and having their terminal ends inserted into and held in suitable orifices 15 in the side of the thermometer 5, the ends of said wires extending into the mercury tube so that the column of mercury, on rising through an increase in temperature, will, at a certain -pre-determined height, form an electrical connection between the terminal ends of the said wires, thereby closing the electric circuit and causing the alarm bell to operate.

16 are rods secured to the binding screws 12 and extending upwardly therefrom into the cylinders 17 Secured in the cylindrical end portions 11 of the cross bar 10. The rods 16 which are preferably of brass are supported from contact with the metal parts of the cross bar 10 by a filling 18 of shellac, paraffin, or other fusible insulating cement.

In the use of this device, there is ordi narily no strain whatsoever upon the rods 16 or upon the cement holding them in their vertical position. An abnormal increase in temperature causes the mercury column to rise to close the alarm signal circuit.

If the thermometer is broken by any means, the cross bar 10 is supported against the pressure of the spring tongue by the fusible cement in the cylinders 17 and in the event of the temperature rising to an abnormal heat the cement is softened and the pressure of the spring tongue forces the bar l() downwardly until it rests upon the end of the rods 16. An electrical connection is thus established between the binding posts to close the alarm circuit.

It will be readily seen that a device such as described will operate very readily on the rise of temperature through the electrical connection established by the mercury column but that in the eventof failure of the mercury column through breakage, the device will still act to give warning.

lVhat I claim as my invention is 1. In an automatic fire alarm, an electrically operated signal, a pair of leads from the signal circuit having branched ends, a thermometer having its mercury column arranged to close the electrical circuit through onel pair of said branches at a pre-determined temperature, and means adapted to automatically close the electrical connection of the circuit through the other branches at a |pre-determined temperature in the event of the thermometer being broken.

2. In an automatic fire alarm, an electrically operated signal, a pair of leads from the signal circuit having branched ends, a thermometer having it-s mercpry column ar ranged to close the electrical circuit through one pair of said branches at a pre-determined temperature, an electrical conductor supported by said thermometer adjacent to the terminal ends of the other pair of branched ends of said leads and adapted to be moved into contact therewith following the breaking of the thermometer, and an insulating fusible cement holding said electrical conductor out of contact with said secondary branch terminals.

3. In an automatic lire alarm, an electrically operated signal, a pair of leads from the signal circuit having branched ends, a thermometer having its mercury column arranged to close the electrical circuit through one pair of said branches at a pre-determined temperature, a metallic cross bar supported by said thermometer and having tubular extensions therefrom, a pair of electric terminals forming the secondary branches of said electric circuit xtending into said tubular extensions, and a fusible insulating cement arranged Within said tubular extensions and embracing said terminals, said cement being adapted to hold the electrical conductor from electrical contact with said terminals to a slightly higher tem perature than the temperature at which the electrical circuit to the former terminals Would be closed by the mercury column.

4L. In an automatic lire alarm, a supporting plate, a. thermometer supported from said plate, an alarm circuit having a pair of electrical terminals inserted into said thermometer and adapted to be electrically connected together on the risc of the mcrcury column, a pair of electric terminals arranged one to each side of said thermometer and electrically connected to the aforesaid terminals, a bar supported on the top of said thermometer above said latter termi nals and supported from said terminals by a fusible insulating cement, and a spring member secured to said supporting plate and bearing downwardly against said cross bar.

Signed at the city of Toronto, county of York, Ontario, Canada, this 13th day of October 1911.

MALCOLM GBSON. lVitnesses H. DENNISON, E. HEnoN.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Eatents, Washington, D. C. 

